Entomophagy is defined as the practice of eating insects, usually reserved for people. Insectivory is "feeding" on insects, usually reserved for animals.
In my dissertation and subsequent work on our hominin ancestors, specifically South African robust australopithecines, I chose to use insectivory regarding their behavior, following the vernacular of primatologists whose work was essential in creating my models. Although the suffix -ivore is meant to imply specialization such that over half of the diet comes from that resource, primatologists discuss the degree of folivory, frugivory, insectivory, etc. across species that do not specialize on those resources, blurring the lines of the definitions.
One of my next projects, which I will be presenting at the AAA meetings in Chicago next month, investigates patterns of insects-as-food across different human populations of foragers and horticulturalists. When referring to their insect consumption, I obviously use the word entomophagy.
I am now working on a book project that includes a theoretical reconstruction of the role of insects across all of human evolution. In order to fill in the gap between australopithecines and people today, I am going to pay particular attention to Homo erectus and Neandertals. I actually do not think Neandertals ate many insects due to the lack of biodiversity in northern latitudes (which is also an interesting extra piece to the puzzle as to why entomophagy is not favored in the United States and Europe..). However, I would readily credit any insects consumed by Neandertals as entomophagy, likely due to my stance that Neandertals are are not a distinct species different from modern humans. Neandertals are people, too!
That leaves Homo erectus, a species with hallmark increases in both brain and body size which make them seem much more human-like. Is it the degree of insectivory or the degree of entomophagy that I am trying to reconstruct for these hominins?
In all honesty, I dislike the term entomophagy. It reminds me of other –phagies, such as geophagy and coprophagy, which are terms that describe the inclusion of things in the diet that would not generally be there under normal circumstances. In this light, I believe entomophagy retains stigma. Although insectivory reduces the practice to animal-like feeding, it is at least a normal behavior and one that is often critical for receiving adequate nutrition at that.
I have not settled on an answer for Homo erectus. On one hand, using insectivory allows me to prolong the use of my preferred term and I do not think there is any offense to be taken through implication that Homo erectus are not people. On the other hand, removing stigma from entomophagy, the word and the practice, is necessary in promoting insects as food, so the more it is used, the more “normal” it may seem.